Wednesday, November 17, 2010

November 17th Wednesday Period 2 (Spring Story)

We started by discussing the homework. We had to describe changes in energy in a story.

1. The spring is pushed down
2. then its released and shoots
3. then it stops going upward and is in midair.
4. it next starts to drop
5. lastly it is caught

On the white boards we wrote the energy transfers for each step and discussed it as a group.

1. We agreed that there was positive work done that transfered it from no energy to elastic potential energy.
2. For this one the spring changed from elastic potential energy to kinetic energy.
3. No the spring loses all of its kinetic energy but has gravitational potentioal energy.
4. The spring loses gravitational potentioal and does downward gaining kinetic energy.
5. Finally the spring is caught where there is negative work aplied to the spring to make ot stop.

We next lodoked at a table with various amounts of force, displacement an work.
We instantly saw that the force times the displacement equals work. Mr. Finley then told us to think of what negative work is. Many groups came up with the idea that negative work is the opposite of work such as negative kinetic energy would be slowing something down or stopping it.



  1. I think this is explained very well, and I completely agree. I am not sure if this is correct but my group also thought of what negative force was. We thought is was when the energy is stopped from doing work.


  2. @AL
    I'm pretty sure negative force is when the force takes away the Joules; for example
    if you catch a falling object, you take away its x number of Joules by catching it. I'm pretty sure that's negative force.